Effects on interface barrier energies of metal-aluminum oxide-semiconductor (MAS) structures as a function of metal electrode material, charge trapping, and annealing

Energy barrier heights at the interfaces of metal-aluminum oxide-silicon structures have been measured via internal photoemission as a function of metal electrode material, premetallization annealing treatment, and charge trapping. Barrier heights at the Si–Al2O3 interface were insensitive to gate metal, annealing treatment, and charge trapping. Zero-field energy barriers for the Au, Ni, Al, or Mg and Al2O3 interfaces were found to be 4.1±0.1, 3.7±0.1, 3.2±0.1, and 2.5±0.1 eV, respectively. Effects of charge trapping on the barrier height were measurable only for the Mg–Al2O3 interface. Annealing treatments had no effects on barrier heights within the accuracy of the measurement technique.